Hi avforums peeps,
I have a pair of very tatty QUAD II monoblocks, which appear to have metal tubes in place of the expected GZ34. It seems they may have been converted to solid-state rectification? The metal tube on one of them bears an inscription which looks like CE612D 50uFX2. 500V. -. COM. NEG. ECE-M500VD50E 503.
Be that as it may, they sound fine. Recently, one of the KT66s stopped lighting up, though the amps *still* sound OK. Even if I remove the 'dark' tube, both amps still work. For a short while, I ran them with 4 used EL34s that fell into my clutches, and they still worked fine. (Ah, these fragile, temperamental old prima-donnas) I only stopped using them because I heard EL34s could cause problems for the transformers in standard circuit configuration (or something....it sounded complicated.) I did hear a rumour that a simple circuit modification could make it safe to use either EL34s or KT66s. I have no idea if this mod has been applied to my little grey locomotives. So....some questions, if I may pick the brain of the hive mind?
If the EL34-friendly mod is performed, so the amps work safely with EL34 valves:
1) will the amps still perform well with KT66 valves?
2) will EL34 and KT66 valves produce equivalent power? (if one is 'understressed', will it last longer?)
3) can 5881 and/or 6l6GC valves be safely used ? With good performance?
4) can 5881 and/or 6l6GC and/or KT66 and/or EL34 valves be mixed and matched in the same amp at the same time? i.e. 1 EL34 and 1 KT66?
If the EL34-friendly mod is NOT performed
5) can 5881 and/or 6l6GC valves be safely used ? With good performance?
6) can 5881 and/or 6l6GC and/or KT66 valves be mixed and matched in the same amp at the same time? i.e. 1 5881 and 1 KT66?
Irrespective of the mod ('Irregardless', as they say in the classics)
7) Several years ago, I heard of issues with some new production KT66 valves that caused problems for some amps, particularly the QUAD II. The name Golden Dragon comes to mind, but I can't be sure. Do I have that right? Is this still an issue? Will I be safe from catastrophe if I avoid this brand for KT66 valves?
8) 6L6GCs seem to be cheaper than KT66s, and 5881s and EL34s cheaper still - is this impression valid? Does it seem like a reasonable plan, in these dark days, to feed one's QUAD II a diet of these cheaper valves, perhaps until one's ship comes in?
9) Will any harm come to my amps if I run them each with a single KT66 (or perhaps 5881 or 6l6GC, but I have 3 working KT66s?) If suitably modded for the EL34, will they be OK with a single EL34 each?
10) why is the number 8 followed by a close bracket imterpreted as a cool yellow face emoticon? I see it's the 8th emoticon, but why does this not happen to the others?
Some interesting Amazon links(I just happened to be in the neighbourhood):
An Amazon entity called "Behringer" is selling "BUGERA BUGERA 6L6GC-4" (http://www.amazon.com/Behringer-6L6GC-4-BUGERA/dp/B002GHC04Y/ref=sr_1_5?ie=UTF8&qid=1414362936&sr=8-5&keywords=6l6gc) I think I would like to have BUGERA BUGERA valves in my amps. It sounds quite rude.
Amazon entitly "AmplifiedParts" is selling a Mullard Reissue EL34 Power Vacuum Tube, Matched Quad by Mullard http://www.amazon.com/Mullard-Reissue-Power-Vacuum-Matched/dp/B004XJCLOW/ref=sr_1_11?ie=UTF8&qid=1414367459&sr=8-11&keywords=el34
Amazon entity TubeDepot seem to be selling Sovtek 5881/6L6WGC Power Tubes (Pair) (http://www.amazon.com/Sovtek-5881-6L6WGC-Power-Tubes/dp/B0002ORP7A/ref=sr_1_2?ie=UTF8&qid=1414367164&sr=8-2&keywords=5881)
Are these brands like Sovetek, Behringer, Mullard , tubedepot, really selling via Amazon? I have used the A for other things , with satisfactory results, so am tempted to do my valve shopping there as well, while Mr Valve seem to be struggling with the PO strike.
Ek dank u by voorbaat
I have a pair of very tatty QUAD II monoblocks, which appear to have metal tubes in place of the expected GZ34. It seems they may have been converted to solid-state rectification? The metal tube on one of them bears an inscription which looks like CE612D 50uFX2. 500V. -. COM. NEG. ECE-M500VD50E 503.
Be that as it may, they sound fine. Recently, one of the KT66s stopped lighting up, though the amps *still* sound OK. Even if I remove the 'dark' tube, both amps still work. For a short while, I ran them with 4 used EL34s that fell into my clutches, and they still worked fine. (Ah, these fragile, temperamental old prima-donnas) I only stopped using them because I heard EL34s could cause problems for the transformers in standard circuit configuration (or something....it sounded complicated.) I did hear a rumour that a simple circuit modification could make it safe to use either EL34s or KT66s. I have no idea if this mod has been applied to my little grey locomotives. So....some questions, if I may pick the brain of the hive mind?
If the EL34-friendly mod is performed, so the amps work safely with EL34 valves:
1) will the amps still perform well with KT66 valves?
2) will EL34 and KT66 valves produce equivalent power? (if one is 'understressed', will it last longer?)
3) can 5881 and/or 6l6GC valves be safely used ? With good performance?
4) can 5881 and/or 6l6GC and/or KT66 and/or EL34 valves be mixed and matched in the same amp at the same time? i.e. 1 EL34 and 1 KT66?
If the EL34-friendly mod is NOT performed
5) can 5881 and/or 6l6GC valves be safely used ? With good performance?
6) can 5881 and/or 6l6GC and/or KT66 valves be mixed and matched in the same amp at the same time? i.e. 1 5881 and 1 KT66?
Irrespective of the mod ('Irregardless', as they say in the classics)
7) Several years ago, I heard of issues with some new production KT66 valves that caused problems for some amps, particularly the QUAD II. The name Golden Dragon comes to mind, but I can't be sure. Do I have that right? Is this still an issue? Will I be safe from catastrophe if I avoid this brand for KT66 valves?
8) 6L6GCs seem to be cheaper than KT66s, and 5881s and EL34s cheaper still - is this impression valid? Does it seem like a reasonable plan, in these dark days, to feed one's QUAD II a diet of these cheaper valves, perhaps until one's ship comes in?
9) Will any harm come to my amps if I run them each with a single KT66 (or perhaps 5881 or 6l6GC, but I have 3 working KT66s?) If suitably modded for the EL34, will they be OK with a single EL34 each?
10) why is the number 8 followed by a close bracket imterpreted as a cool yellow face emoticon? I see it's the 8th emoticon, but why does this not happen to the others?
Some interesting Amazon links(I just happened to be in the neighbourhood):
An Amazon entity called "Behringer" is selling "BUGERA BUGERA 6L6GC-4" (http://www.amazon.com/Behringer-6L6GC-4-BUGERA/dp/B002GHC04Y/ref=sr_1_5?ie=UTF8&qid=1414362936&sr=8-5&keywords=6l6gc) I think I would like to have BUGERA BUGERA valves in my amps. It sounds quite rude.
Amazon entitly "AmplifiedParts" is selling a Mullard Reissue EL34 Power Vacuum Tube, Matched Quad by Mullard http://www.amazon.com/Mullard-Reissue-Power-Vacuum-Matched/dp/B004XJCLOW/ref=sr_1_11?ie=UTF8&qid=1414367459&sr=8-11&keywords=el34
Amazon entity TubeDepot seem to be selling Sovtek 5881/6L6WGC Power Tubes (Pair) (http://www.amazon.com/Sovtek-5881-6L6WGC-Power-Tubes/dp/B0002ORP7A/ref=sr_1_2?ie=UTF8&qid=1414367164&sr=8-2&keywords=5881)
Are these brands like Sovetek, Behringer, Mullard , tubedepot, really selling via Amazon? I have used the A for other things , with satisfactory results, so am tempted to do my valve shopping there as well, while Mr Valve seem to be struggling with the PO strike.
Ek dank u by voorbaat
